1. Field of the Invention
This invention relates to an input hopper which transfers cards and the like from a stack into a module for processing.
2. Description of the Prior Art
Sheet and card feeding mechanisms are in wide spread use. There are many systems requiring the input of sheets or cards. The systems separate a card from a stack of cards and feed the card into the system. A major problem associated with card feeders is that a card often jams or sticks. This may cause damage to the system and costly downtime. Numerous devices to circumvent the problem of a jammed or sticky card have been disclosed.
Earlier methods included various ways to prevent further feeding of cards once a jam was located downstream. U.S. Pat. No. 1,959,854, 2,510,559 and 3,002,750 are representative of this. However, a problem associated with this approach is that many cards or sheets may be fed to cause the jam, thus causing considerable downtime in clearing the jam. The jam also has the potential to cause considerable damage to the machine, sheets or cards.
Another approach taken in U.S. Pat. No. 4,302,000 is to decrease or increase the force applied to the stack and thus diminish the possibility of a jam. This is only acceptable for compressible stacks such as paper and even then is not a fool proof method to deal with jams.
The wide spread use and manufacturing of cards today have put high demand on an efficient input hopper system. The high speed input hoppers of today have introduced problems associated with the input of cards which have not been addressed in the prior art. Stacks of blank cards are commonly made by punching a prescribed shape through a stack comprising many sheets of plastic. The resultant stack of cards often contain burrs on the edges. The burrs tend to interlock amongst themselves thereby making it difficult for a single card to be removed from the stack. Thus it is critical that the input hopper system for these cards be able to sense when a card is stuck and shut down before damage occurs.
There are numerous embossing machines on the market today which utilize an input hopper system for plastic credit cards. U.S. Pat. No. 4,384,711 utilizes an input hopper system with a positioning cam. The cam comprises a card shelf moving vertically in a two dimensional plane. The shelf engages a bottom edge of a single card from a stack and pushes the card in a shearing direction away from the stack. The shelf or drive mechanism may become damaged when the required shear force becomes too great, thus the system has been modified by adding a spring which extends when the force to push the card is greater than the force of the spring. This spring prevents the card picking mechanism from damaging itself when a card requires a shear force greater than the strength of mechanism components.
DataCard model 4000 is an embossing system that utilizes card picker shafts to shear a card from a stack of cards. Each shaft comprises a vertically moving pronged element interconnected to a spring in a fashion similar to U.S. Pat. No. 4,384,711. The pronged picker moves in a two-dimensional field and shears a card from the bottom in an upwardly fashion. However, the picker does not always successfully shear both ends of the card from the stack, and may leave one side up and one side down. As a result, the card does not successfully leave the input hopper system and temporarily halts the system. A further problem with the 4000 system is that the linear drive motion is more costly than a rotary drive motion. The linear system is bulky in that a drive shaft must extend in the vertical direction as well as the horizontal direction.
U.S. Pat. No. 4,519,600 utilizes an input hopper system which at first glance appears somewhat similar to the present invention in that a motor drives a pulley which is linked through a series of belts and shafts to a picker cam and a roller assembly. However, in addition to other differences, when a card is stuck to the rest of the stack, the force required to free the card from the stack often exceeds the force of the clamping screw on the output arm or the set screw on the picker cam. The picker cam shaft may then become misaligned, thus requiring the hopper assembly to be serviced. This results in lengthy and costly downtime for the input hopper.
It is, therefore, evident that there is a need for a low maintenance input hopper system. Large embossing systems emboss large quantities of cards and any downtime results in substantial repair costs and reduced card production. The present invention provides an input hopper system which reduces downtime and costly repairs and provides high speed input of cards into the embossing system.